Project Summary Alcohol use disorders (AUDs) represent a widespread health and economic problem in the United States. Available treatments are not very effective, in part due to limited knowledge of the mechanism of the development and maintenance of alcohol dependence. Whole tissue gene expression studies have provided a great deal of insight into how molecular pathways may be regulated and altered in response to chronic alcohol exposure, but it is still unknown how different cell types may be contributing to the molecular changes that could be driving AUDs. The proposed research will investigate the role of astrocytes in chronic ethanol drinking. Astrocytes are a critically important cell type in the brain and are implicated in many neuropsychiatric diseases, yet little is known about how these cells are affected by chronic alcohol administration. In turn, little is known about how alterations in astrocyte function could impact escalation of alcohol consumption. Specific Aim 1 will identify astrocyte-specific transcriptional changes by performing RNA-sequencing on astrocytes isolated from mice chronically exposed to ethanol. This aim will not only provide candidate targets for Aim 3, but will increase our understanding of the functional changes occurring in astrocytes, as well as gene networks important for astrocyte pathology. Specific Aim 2 will examine the behavioral consequences of astrocyte-specific calcium signaling activation. Calcium signaling in astrocytes is a newly discovered mechanism for astrocyte modulation of synaptic transmission. This aim will determine if activation of calcium signaling pathways in astrocytes using Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) alters chronic ethanol consumption. Specific Aim 3 will determine the behavioral impact of astrocyte-specific gene manipulation. In this aim, candidate genes identified in Aim 1 will be knocked down in astrocytes and tested for their role in chronic ethanol consumption. This study will be the first to identify the astrocyte-specific transcriptional response to chronic ethanol and will lead to a clearer understanding of how alcohol abuse impacts the brain. This information will ultimately be used to develop more specific and targeted therapies to treat AUDs. In addition, since astrocyte dysfunction is a common feature of many neurological conditions, including Alzheimer's disease and epilepsy, knowledge of the molecular features of alcohol-induced astrocyte responses could be of use to other groups studying the astrocyte contribution to neurological disease.